/*
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 * and open the template in the editor.
 */
package elevenHomework;

/**
 *
 * @author Administrator
 */
import java.util.LinkedHashSet;
import java.util.Scanner;
 
/**
 *
 * @author FuQianMing
 */

 
   import java.io.BufferedInputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
  
public class  ProblemG1 {
  
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
       Scanner cin = new Scanner(new BufferedInputStream(System.in));
       String str = cin.next();
        System.out.print(str.charAt(0));
       for(int i=1; i< str.length(); i++){
          boolean shouldPrint = true;
          for(int j=0; j<i; j++){
              if(str.charAt(j) == str.charAt(i)){
                  shouldPrint = false;
                  break;
              }
          }
          if(shouldPrint) System.out.print(str.charAt(i));
       }
       System.out.println();
}
}
